Spectrally sensitized silver halide photographic emulsions

ABSTRACT

A silver halide photographic emulsion having high spectral sensitivity in the range 510-533 m Mu containing at least one sensitizing dye represented by the following formula (1):   WHEREIN Z1 and Z2 each represent a group of nonmetallic atoms necessary to complete a benzene ring, the hydrogen atoms of which may be substituted by substituents.

Sato et al.

[4 1 Feb. 19, 1974 SPECTRALLY SENSITIZED SILVER HALIDE PHOTOGRAPHICEMULSIONS [75] Inventors: Akira Sato; Keisuke Shiba; Haruo Takei, all ofKanagawa, Japan [73] Assignee: Fuji Photo Film Co., Ltd.,

Kanagawa, Japan [22] Filed: Feb. 17, 1972 [21] Appl. N0.:.227,026

[30] Foreign Application Priority Data Feb. 18, 1971 Japan 46-7525 [52]US. Cl. 96/137, 260/240.6 [51] Int. Cl G03c 1/18 [58] Field of Search96/ 1-37 [56] References Cited UNITED STATES PATENTS 2,918,369 12/1959Doorenbos 96/132 3,244,526 4/1966 Copeland 96/132 3,656,957 4/1972Oliver et al. 96/127 Primary Examiner-J. Travis Brown Attorney, Agent,or Firm-Sughrue, Rothwell, Mion, Zinn & Macpeak ABSTRACT A silver halidephotographic emulsion having high spectral sensitivity in the range510-533 mp. containing at least one sensitizing dye represented by thefollowing formula (1):

wherein Z and Z each represent a group of nonmetallic atoms necessary tocomplete a benzene ring, the hydrogen atoms of which may be substitutedby substituents.

8 Claims, 1 Drawing Figure SPECTRALLY SENSITIZED SILVER HALIDEPHOTOGRAPHIC EMULSIONS The present invention relates to silver halidephotographic emulsions containing new sensitizing dyes, and particularlyto silver halide photographic emulsions having a high spectralsensitivity at a range of 5 l0 533 mu.

it has been well-known that the sensitive wave length range of silverhalide emulsions is extended by addition of sensitizing dyes thereto andthe silver halide emulsions are spectrally sensitized.

The spectral sensitization often is affected by the chemical structureof the sensitizing dyes. Namely, since the formation of a J-aggregate ofthe sensitizing dyes is influenced by the chemical structure, forexample, kinds of heterocyclic nuclei and kinds of substituents, asensitization of near the spectral sensitization maximum caused by theJ-aggregate of the sensitizing dyes adsorbed on the surface of silverhalide particles is influenced extremely by the chemical structure ofthe sensitizing dyes used. Accordingly, selection of the sensitizing dyeused is very important in the case of highly sensitizing the desiredspecified wave length range of the photographic sensitive material.

The present inventors have found that the following new sensitizing dyesform the J-aggregate and are useful for high spectral sensitization of arange of 510 533 mp.

An object of the present invention is to provide silver halidephotographic emulsions having a high spectral sensitivity at about 510533 my. which do not leave stain after development.

The object of the invention has been attained by adding novelsensitizing dyes represented by the following formula (1) to silverhalide photographic emulsions.

l H N N I :z. =CH--CH=ti7- z '2 X lq N I R2 which are electronattractive substituents known in the common benzimidazolocarbocyaninesinclude halogen atoms (e.g. fluorine atom, chlorine atom and bromideatom), trifluoromethyl group, alkylsulfonyl groups (e.g., amethylsulfonyl group etc.), sulfamyl group, alkylaminosulfonyl groups(e-g-;, methylaminosulfonyl group and ethylaminosulfonyl group),dialkylaininosulfonyl groups (e.g., dimethylaminosulfonyl group,diethylaminosulfonyl group, piperidinosulfonyl group, morpholinosulfonylgroup and .pyrrolidinosulfonyl group etc.), cyano group, carboxyl group,alkoxycarbony] groups (e.g., methoxy-carbonyl group and ethox-*ycarbonyl group etc.) and acyl groups (e.g., acetyl group and benzoylgroup etc.). A preferred substituent is the chlorine atom. Thesubstituents of Z, include alkyl groups (e.g., methyl group etc.),halogen atoms (e.g., fluorine atom, chlorine'atom and bromine atom etc.)and alkoxy groups (e.g., methoxy group etc.). R, and R which areidentical or different each represent an alkyl group preferably havingup to 8 carbon atoms [i.e., unsubstituted alkyl group and substitutedalkyl 2 group; (e.g., methyl group, ethyl group, n-propyl group, n-butylgroup and cyclohexyl group etc. a hydroxyalkyl group (e.g.,B-hydroxyethyl group, 'y-hydroxypropyl group), an acetoxyalkyl group(e.g., B-acetoxyethyl group; 'y-acetoxypropyl group), an alkyl groupcontaining a carboxy radical (e.g., carboxymethyl group, B-carboxyethyl,group, 'y-carboxypropyL group, 8-carboxybutyl group, p-carboxybenzylgroup and p-carboxyphenethyl group), a cyanoalkyl group (e.g.,B-cyanoethyl group, 'y-cyanopropyl group, S-cyanobutyl group), acarbamoylalkyl group (e.g., B-carbamoylethyl group, y-carbamoylpropylgroup, o-carbamoylbutyl group, B-N-ethylcarbamoylethyl group,y-N-ethylcarbamoylpropyl group, 6-N methylcarbamoylbutyl group), asulfamoylalkyl group (e.g. 'y-sulfamoyl propyl group, 'd-sulfamoyl butylgroup), an aminosulfonyl alkyl group (e.g., 'y-N- ethylaminosulfonylpropyl group, 8-N- ethylaminosulfonyl butyl group), an alkyl groupcontaining a sulfo radical (e.g., B-sulfoethyl group, y-sulfopropylgroup, 'y-sulfobutyl group, S-sulfobutyl group, p-sulfobenzyl group andp-sulfophenethyl group), an aralkyl group (e.g., benzyl group, phenethylgroup) and an ally] group (e.g., vinylmethyl group) etc.]. A preferredsubstituent is the substituted alkyl group containing a sulfo or carboxyradical. In the case that one of R and R, has a sulfo radical orcarboxyl radical as the substituent, for example, in the case of'y-sulfopropyl group, it is supposed that an inner salt having thefollowing formula (II) is formed.

611, omen. s 0:

The characteristic of the chemical structure of the sensitizing dyesused in the present invention is that Z, has a benzimidazole nucleus asdefined in formula (1).

a range of about 510 533 mu, since the spectral sensitization rangebecomes broad in the long wave length side.

In the following, typical examples of the new sensitizing dyesrepresented by the formula (1) used in the .present invention are shown.However, they are not intended to be limitative thereof.

Dyel CzHi I H N N g w CHCH=C N N The sentitizing dyes represented by theformula (1) can be prepared by reacting a compound represented by thefollowing formula (III) NR m e mwmmmefi E -CH=CHN N 7 loan. L, I m)wherein 2,, R, and R each represent the same meaning as in formula l Xrepresents an anion (e.g., bromine ion and iodine ion etc.), and nrepresents 0 or 1 (n=0 when the inner salt), with a compound representedby the following formula (IV) in an alcohol in the presence oftriethylamine by heating under reflux. Example of synthesis.

utes in ml of ethanol in the presence of 3ml of triethylamine byrefluxing on a hot water bath. Crystals precipitated on the way of thereaction. After cooling, the

mixture was filtered. By washing with hot ethanol, 0.7g of Dye 5 havingabove 300C- of a boiling point was obtained.

Other dyes could be prepared by the same procedure as abovementioned.

Silver halide photographic emulsions can be spectrally sensitized by thesensitizing dyes used in the present invention. Especially, they areeffective for increasing a'sensitive range of the gelatin-silver halidephotographic emulsions. Further, photographic emulsions containing ahydrophilic colloid besides gelatin such as agar. agar, collodion,cellulosederivatives, polyvinyl alcohol and synthetic or naturalhydrophilic resins can be sensitized by the above-mentioned dyes.

In the emulsions used in the present invention, many kinds of silversalts such as silver bromide, silver iodobromide, silver bromochlorideand silver iodobromochloride can be used.

In order to prepare the sensitized photographic emulsions of the presentinvention, the sensitizing dyes may be added to the photographicemulsions by any common method. In general, the sensitizing dyes areadded to the emulsions as a solution prepared by dissolving in asuitable solvent such as methanol, methyl cellosolve and pyridine etc.The amount "of the sensitizing dyes added to the emulsions can vary in arange of 5-200 mg of dye per kg of the emulsions according to thedesirable efiect. However, this amountis not limitative.

Known sensitizing dyes may be added additionally to the photographicemulsions of the .present invention.

At production of the photographic emulsions of the present invention,sensitizing agents, stabilizers, toning agents, hardening agents,surface active agents, antifogging agents, plasticisers, developmentaccelerators, color formers, fluorescent whitening agents andultraviolet ray absorbing agents can be added to the emulsion by anycommon method.

The photographic emulsions of the present invention can be applied tosuitable supports, for example, glass films of cellulose derivatives,films of synthetic resins, baryta paper, resin coated paper andsynthetic paper by any common method.

In the following, examples are shown.

Silver halide photographic emulsions were prepared by adding sensitizingdyes above-mentioned to a gelatin silver iodobromide emulsion (molarratio: Br I 93 v 7). The emulsions were applied to cellulose triacetatefilms. After drying, the films were exposed to light through a yellowfilter made by Fuji Photo Film Co. (filter through which rays having awave length of longer than 480 my. pass) using a day-light lamp of 64 5luxes (corresponding to 5,400K) and developed. The developer having thecomposition represented in Table l was used. 7

TABLE 1 Metal 2 g Sodium sulfite 1 g Hydroquinone 5 g Borax' 2 8 Waterto make 1 liter In Table 2, spectral sensitization and wave length ofthe sensitization maximum obtained by adding the sensitizing dyes of thepresent invention and sensitizing dyes for comparison to the silveriodobromide emulsion are shown.

TABLE 2 Ex. Dye No. Amount of Wave length R9) tive No. dye (2 l0" ospectr molar sensitization sensitivity concentration maximum mg.

ml/ 100 g of H emulsion) 1 1 s 515 I00 2 2 8 520 225 3 3 8 5l2 140 4 4 8520 lZO 5 5 8 530 283 6 6 8 530 280 7 7 8 532 295 8 8 8 532 283 A 8 540105 (comparison) B 8 534 I00 (comparison) C 8 520 (comparison) D 8 544(comparison) The spectral sensitivity is represented by a relativesensitivity which is obtained by supposing that the spectral sensitivityof the sensitizing dye (B) is 100 when exposed to light using a yellowfilter.

The sensitizing dyes used for comparison are those having the followingchemical structure. 4

(D) sH;

V The FIGURE shows curves of the spectral sensitivity of the silverhalide emulsions containing sensitizing dye 7 which is the typicalexample of the sensitizing dyes used in the present invention (shown asthe solid line) and sensitizing dye for comparison (A) (shown as thedotted line).

As being clear from the table and the FIGURE, it will be understood thatthe sensitizing dyes used in the present invention form the J-aggregate,and the photographic emulsions containing said dyes have excellentphotographic characteristics in that they have a high spectralsensitivity and an excellent sharp cut property in a long wave lengthside. Brief explanation of drawmg:

The FIGURE shows curves of the spectral sensitivity. In the FIGURE, (7)and (A) represent curves of the spectral sensitivity of photographicemulsions containing the sensitizing dye (7) used in the presentinvention and the dye used for comparison (A), respectively.

What is claimed is:

1. A silver halide photographic emulsion which contains at least asensitizing dye represented by the following formula:

wherein Z, and Z each represent a group of nonmetallic atoms necessaryto complete a benzene ring, and R, and R each represent an identical ordifferent alkyl group.

2. An emulsion as claimed in claim 1 wherein the alkyl group of R, or Ris an alkyl group containing a sulfo or carboxy radical.

3. An emulsion as claimed in claim 1 wherein the benzene ring of Z, issubstituted by the chlorine atom.

awa (I

2. An emulsion as claimed in claim 1 wherein the alkyl group of R1 or R2is an alkyl group containing a sulfo or carboxy radical.
 3. An emulsionas claimed in claim 1 wherein the benzene ring of Z1 is substituted bythe chlorine atom.
 4. An emulsion as claimed in claim 1 wherein thesilver halide is silver iodobromide.
 5. A light-sensitive silver halidephotographic material which comprises a layer containing the silverhalide emulsion as claimed in claim
 1. 6. An emulsion as claimed inclaim 1, wherein the sensitizing dye is selected from the groupconsisting of:
 7. An emulsion as claimed in claim 1 wherein the alkylgroup is a member selected from the group consisting of unsubstitutedalkyl having up to 8 carbon atoms, hydroxyalkyl, acetoxyalkyl,carboxyalkyl, cyanoalkyl, carbamoylalkyl, sulfamoylalkyl,aminosulfonylalkyl, sulfoalkyl, aralkyl and allyl.
 8. An emulsion asclaimed in claim 1 wherein said alkyl group is a member selected fromthe group consisting of methyl, ethyl, n-propyl, n-butyl, cyclohexyl,Beta -hydroxyethyl, gamma -hydroxypropyl, Beta -acetoxyethyl, gamma-acetoxypropyl, carboxymethyl, Beta -carboxyethyl, gamma -carboxypropyl,delta -carboxybutyl, p-carboxybenzyl, p-carboxyphenethyl, Beta-cyanoethyl, gamma -cyanopropyl, delta -cyanobutyl, Beta-carbamoylethyl, gamma -carbamoylpropyl, delta -carbamoylbutyl, Beta-N-ethylcarbamoylethyl, gamma -N-ethylcarbamoylpropyl, delta-N-methylcarbamoylbutyl, gamma -sulfamoyl propyl, delta -sulfamoylbutyl, gamma -N-ethylaminosulfonyl propyl, delta -N-ethylaminosulfonylbutyl, Beta -sulfoethyl, gamma -sulfopropyl, gamma -sulfobutyl, delta-sulfobutyl, p-sulfobenzyl, p-sulfophenethyl, benzyl, phenethyl, andvinylmethyl.